The present invention relates to a magnetoresistive effect composite head and a method of manufacturing the same and, more particularly, to a magnetoresistive effect composite head consisting of a read head and an inductive recording head that utilize the magnetoresistive effect, and a method of manufacturing the same.
As the magnetic recording medium is becoming downsized and its capacity is becoming large, the relative speed between the read magnetic head and the magnetic recording medium is becoming low, and therefore demand has arisen for a magnetoresistive effect head (to be referred to as an MR head hereinafter) whose read output does not depend on the speed. This MR head is discussed in "A Magnetoresistive Readout Transducer", IEEE TRANSACTIONS ON MAGNETICS, VOL. MAG-7, NO. 1, pp. 150-154, MARCH 1971.
As the most typical MR head, a magnetoresistive effect composite head (to be referred to as a composite head hereinafter) consisting of an MR head (MR element portion) and an inductive head (to be referred to as an ID head or ID element portion hereinafter) has been put into practical use.
The MR head is used to read information, and consists of two magnetic shield films arranged to be substantially parallel to a slider floating surface, i.e., an Air Bearing Surface (ABS), opposing the magnetic disk medium, and a magnetoresistive effect element present between the two magnetic shield films through magnetic isolation layers each made of an insulator.
The ID head has, as its one magnetic pole, the other magnetic shield film (upper shield) of the two magnetic shield films described above. A coil sandwiched by insulators and the other magnetic pole having a pole-like distal end portion and an angular end face are stacked on a surface of one magnetic pole on a side opposite to the magnetoresistive effect element to be parallel to one magnetic pole described above. Information is recorded by a magnetic field generated in a magnetic gap arranged between one magnetic pole and the other magnetic pole.
Originally, the other magnetic pole P2 of the ID head is formed in a magnetic field so that its magnetic anisotropy is formed in the widthwise direction, as indicated by an arrow A in FIG. 8, and is further heat-treated in the magnetic field.
As the recording density increases, the width of the other magnetic pole P2 particularly near the ABS surface decreases sharply. Accordingly, a phenomenon has become conspicuous in which the magnetic anisotropy formed by film deposition and heat treatment is strongly influenced by the shaping effect of the decrease in width and is rotated through 90.degree., as indicated by an arrow A' in FIG. 9. The reason for this is as follows. Along with an increase in recording density, when the width of the pole-like distal end portion of the other magnetic pole decreases, the magnetic anisotropy of the other magnetic pole becomes difficult to form, and tends to be formed in a direction parallel to the direction of recording magnetic field due to the shaping effect.
The direction of magnetic anisotropy of one magnetic pole of the ID head serving also as the upper shield and that of the other magnetic pole of the ID head corresponding to it must be perpendicular to the direction of recording magnetic field in order to improve the recording characteristics in a high-frequency range. Therefore, when the width of the pole-like distal end portion of the other magnetic pole decreases, an apparent degradation occurs in the recording characteristics in the high-frequency range.